1. Field of the Invention
The present invention relates to a data recording system of a magneto-optic type using a magneto-optic disk and, more particularly, to a magneto-optically data recording system that enables to record and reproduce analog signals of multiple channels as well as to search at a high speed.
2. Description of Related Art
Heretofore, there have been employed apparatuses and systems of magnetically recording tape type, e.g. of open reel type, video cassette type, compact cassette type, DAT tape type, and so on as apparatuses and systems for continuously recording analog signals, such as biological signals, e.g. electroencephalogram, pulses etc., signals indicative of mechanical vibration etc., signals indicative of a variation in temperatures during a chemical reaction etc., and so on, in multiple channels for a long period of time.
However, it should be noted that such apparatuses and system of recording tape type are arranged so as to write or read data while one band of the tape is brought into direct contact with their magnetic head one after another, so that they can produce only sequential files from the principle point of view. Hence, when several kinds of analog data are recorded on one tape, e.g. when data of a first analog phenomenon A are recorded for 50 minutes, data of a second analog phenomenon B are recorded, and data of a third analog phenomenon C are recorded for 50 minutes, an index for the searching contents of the phenomena recorded cannot be recorded at one location, e.g. at a top of the tape. Therefore, in order to allow a certain phenomenon at a particular location to be searched for after recording, there is no way but to read a sequence of the phenomena one after another from the top of the tape and no random search for such a certain phenomenon can be implemented.
Further, it is to be noted that it may take 40 seconds or longer to find data located at the last location of a tape having a recording capacity of 120 minutes when the reading magnetic head is located at the top of the tape even if a search is performed by using an apparatus of a latest DAT type at a speed as fast as a limit speed of 200 times. Further, the apparatuses and systems should be operated by frequently repeating running, suspending and reversing of the tape, so that the tape is expanded or retracted whenever it is caused to run, suspended and reversed, thereby causing a variation in expansion or in winding of the tape and as a consequence incurring mechanical damages upon the tape. As a result, reliability of the data recorded may be lost, whereby incurable defects may arise for the data recording apparatuses and systems that should read and write the data recorded at many repetitive occasions.